Field of the Invention
The present invention relates to a system and method of flying tethered vehicles in high wind speeds.
Description of Related Art
Crosswind kite systems comprising tethered wings (kites) can extract useful power from the wind for purposes such as, for example, generating electricity, lifting or towing objects or vehicles, etc. To provide or use consistent power, it may be desired to fly the kite in repeating trajectories (i.e., a limit cycle). It may also be desired to maintain the kite aloft and flying consistent trajectories during a large range of environmental conditions such as high wind speeds, large gusts, turbulent air, or variable wind conditions. However, with the typical crosswind kite system mode of operation, the inertial speed of the kite, the tension on the tether, the aerodynamic loads on the kite structure and the system power output increase as the wind speed increases. So, for example, a problem arises in times of high winds, when tether tension or kite structural load exceeds a safety limit. Therefore, an alternative mode of operation is desired so that a crosswind kite system can maintain bounded loads and bounded power generation while flying in limit cycles in high and changing winds.